In a known manner, a mechanism operating on an appliance can be activated by:                a dialogue box asking the user to confirm his intention; on a mobile telephone for example, the keypad switches to locked mode after a certain length of time, i.e. simply pressing a key on the keypad does not trigger the anticipated action as unlocking requires that several predetermined keys be pressed successively in a predefined sequence;        entry of a password, as is the case for activating the unlocking mechanism of a session on a computer, mobile telephone or communication device (PDA, etc.);        use of a code located in a “keychain” accessible by the appliance after user authorization.        
A major drawback of activating a mechanism using the first or second type of method is that the activation of the mechanism does not check the will of the user. Such entry can become a reflex action.
The major drawback of the third type of method is that the user cannot necessarily remember the applications that he has authorized to access his keychain and that the request for authorization to use one of his keys (password, for example) is not submitted to it.